POJ 1056 IMMEDIATE DECODABILITY (字典树)

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<iostream>
using namespace std;

const int MAXN = 2;
typedef struct Trie_Node
{
    bool isCode;
    struct Trie_Node *next[MAXN];
}Trie;
bool flag;

void Trie_insert(Trie *root,char *str)
{
    Trie *p=root;
    int len=strlen(str);
    for(int i=0;i<len;i++)
    {
        int k=str[i]-‘0‘;
        if(p->next[k]==NULL)
        {
            Trie *t=new Trie;
            for(int j=0;j<MAXN;j++)
                t->next[j]=NULL;
            t->isCode=false;
            p->next[k]=t;
        }
        else
        {
            if(p->next[k]->isCode)
            {
                flag=false;
                return;
            }
        }
        p=p->next[k];
    }
    p->isCode=true;
}
void Trie_del(Trie *root)
{
    for(int i=0;i<MAXN;i++)
    {
        if(root->next[i]!=NULL)
            Trie_del(root->next[i]);
    }
    free(root);
}
char str[15];

int main()
{
    int iCase=0;
    while(scanf("%s",str)!=EOF)
    {
        iCase++;
        Trie *root=new Trie;
        for(int i=0;i<MAXN;i++)
            root->next[i]=NULL;
        root->isCode=false;
        flag=true;
        Trie_insert(root,str);
        while(scanf("%s",str))
        {
            if(str[0]==‘9‘) break;
            if(flag) Trie_insert(root,str);
        }
        if(flag) printf("Set %d is immediately decodable\n",iCase);
        else printf("Set %d is not immediately decodable\n",iCase);
        Trie_del(root);
    }
    return 0;
}